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        검색결과 520

        1.
        2025.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We introduce a new clustering algorithm, MulGuisin (MGS), that can identify distinct galaxy over-densities using topological information from the galaxy distribution. This algorithm was first introduced in an LHC experiment as a Jet Finder software, which looks for particles that clump together in close proximity. The algorithm preferentially considers particles with high energies and merges them only when they are closer than a certain distance to create a jet. MGS shares some similarities with the minimum spanning tree (MST) since it provides both clustering and network-based topology information. Also, similar to the density-based spatial clustering of applications with noise (DBSCAN), MGS uses the ranking or the local density of each particle to construct clustering. In this paper, we compare the performances of clustering algorithms using controlled data and some realistic simulation data as well as the SDSS observation data, and we demonstrate that our new algorithm finds networks most correctly and defines galaxy networks in a way that most closely resembles human vision.
        4,800원
        2.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        진저 비어는 생강과 설탕을 이용한 발효 음료로, 가볍 게 탄산화된 특유의 매운맛이 특징이며, 주로 가정에서 직 접 만들어진다. Ginger bug라는 스타터 컬처를 사용한 자 연적 발효 과정을 통해 만들어지며, 이는 상업용 음료와 달리 발효된 상태의 살아있는 미생물을 포함한다. 이 연 구는 두 가지 다른 방법으로 가정용 진저 비어를 직접 제 조하여 진저 비어의 미생물 군집의 변화를 분석하고자 하 였다. 레시피 1과 2의 발효 결과, 총 균수(aerobic plate count, APC)는 최대 6 log CFU/mL에 도달했고, 효모와 곰팡이 수(yeast and mold, YM)는 6.5 log CFU/mL로 가 장 높았다. 레시피 2에서는 진저 비어를 만들기 전에 ginger bug를 발효하였으므로 알코올 함량이 0.655%까지 증가한 반면, 레시피 1에서는 0.15% 미만이었다. 다양성 분석 결 과, ginger bug에서 높은 수준의 Enterobacteriaceae가 발견 되어 발효 과정과 재료 취급이 미생물 군집 변화에 영향 을 미쳤음을 시사했다. 생강과 진저 비어 전반에서 Lactococcus가 낮은 수준으로 검출되었고, 진저 비어에서 는 셀룰로오스를 분해하는 Trabulsiella 균주가 발견되어 프로바이오틱스 가능성을 시사하였다. 본 연구는 진저 비 어의 미생물 군집에 대한 최초의 연구로, 진저 비어 제조 시 재료로부터 기원한 미생물이 어떻게 변화하는지에 대 한 통찰을 제공한다. 또한, 다양한 환경에서의 발효 조건 이 미생물 군집과 제품의 품질에 미치는 영향을 탐구하는 데 기여할 것이다. 연구 결과는 진저 비어의 품질 향상에 대한 향후 연구에 중요한 자료를 제공할 것이다.
        4,000원
        3.
        2024.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A scintillator using organic materials can be easily manufactured in various shapes and sizes to suit the user’s purpose. A quantum dot (QD)-based scintillator has a number of advantages over commercial scintillators, including emission wavelength control, high-purity emission of a specific wavelength, high photoluminescence efficiency, and good photostability. The organic scintillators doping with various agents into the polymer media to increase scintillation efficiency and to control the emissioning wavelength through energy transfer process. In this study, scintillator enhancement was observed with different QDs material and detection response to gamma and neutron was investigated in energy spectrum. Multishell- structure QDs (CdS/CdZnS/ZnS) were fabricated and utilized to offset the shortcomings of single-shell-structure QDs, and the optical properties and the gamma and neutron detection performance capabilities were evaluated. The results of the evaluation of the detection response of the QD-based scintillator confirmed that the neutron/gamma classification performance was similar to that of a commercial scintillator. Furthermore, the gamma detection efficiency was improved by 34–38% (in the case of 137Cs) compared to a commercial scintillator. This study is especially notable in that the organic scintillator incorporated with the newly fabricated QDs can be utilized for gamma and neutron detection for the operation and decommissioning various nuclear facilities.
        5,500원
        4.
        2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To improve the lithium-ion battery performance and stability, a conducting polymer, which can simultaneously serve as both a conductive additive and a binder, is introduced into the anode. Water-soluble polyaniline:polystyrene sulfonate (PANI:PSS) can be successfully prepared through chemical oxidative polymerization, and their chemical/mechanical properties are adjusted by varying the molecular weight of PSS. As a conductive additive, the PANI with a conjugated double bond structure is introduced between active materials or between the active material and the current collector to provide fast and short electrical pathways. As a binder, the PSS prevents short circuits through strong π‒π stacking interaction with active material, and it exhibits superior adhesion to the current collector, thereby ensuring the maintenance of stable mechanical properties, even under high-speed charging/discharging conditions. Based on the synergistic effect of the intrinsic properties of PANI and PSS, it is confirmed that the anode with PANI:PSS introduced as a binder has about 1.8 times higher bonding strength (0.4 kgf/20 mm) compared to conventional binders. Moreover, since active materials can be additionally added in place of the generally added conductive additives, the total cell capacity increased by about 12.0%, and improved stability is shown with a capacity retention rate of 99.3% even after 200 cycles at a current rate of 0.2 C.
        4,000원
        5.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Core muscles provide important dynamic stabilization of the lumbar spine. The twist sit-up can simultaneously stimulate the external oblique (EO), internal oblique (IO), and transverse abdominis (TrA) muscles. Objectives: The purpose of this study is to investigate the impact of knee angles during twist sit-up exercises and determine the most efficient knee angle for performing this exercise. Design: Cross-sectional study. Methods: The study recruited 30 students from S University regardless of gender. The subjects performed a total of 10 twist sit-ups at five different knee angles (0, 40, 65, 90, and 105 degrees), divided between the ipsilateral and contralateral sides. The thickness of abdominal muscles (EO, IO, and TrA), was measured using ultrasonography on rest position and full contraction position for each angle of knee flexion and compared between angles. Results: There were significant differences in the ipsilateral EO, IO, and TrA muscle thickness at different knee flexion angles (P<0.5). There was a significant difference in the thickness of EO between 0 and 105 degrees and between 40 and 105 degrees (P<0.5), a significant difference in the thickness of IO between 0 and 105 degrees (P<0.5), and a significant difference in the thickness of TrA between 0 and 105 degrees, 40 and 90 degrees, and 65 and 90 degrees (P<0.5). Conclusion: In conclusion, the muscles involved in axial rotation i.e., EO and IO, maximally contract at a knee flexion angle of 105 degrees. Therefore, this may be the most optimal angle to perform twist sit-ups.
        4,000원
        6.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        한반도의 Donacia속에는 2아속에 속하는 6종이 있다(An, 2019). 이 중 Chujo (1941)는 북한 함경북도 웅기에서 채집한 표본을 D. aquatica (Linnaeus, 1758)로 보고하였고, Kimoto and Kawase (1966)는 D. japana로 표기하여 보고하였다. 그리고 Hayashi (2020)는 한국에 기록된 D. japana가 D. aquatica로 오인되었을 수 있다고 밝혔다. 이러한 혼란을 해결하기 위해 본 연구는 한국(포천과 울산)에서 채집한 표본과 D. japana에 대한 기재문, 수컷생식기와 같은 형태적인 부분(Hayashi, 2020), COI 유전자 염기서열을 비교하였다. 그 결과로 한반도에 기록된 D. japana은 D. aquatica로 대체되고, D. japana는 일본 고유종이라고 결론을 내리고자 한다.
        4,000원
        7.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Black ice, a thin and nearly invisible ice layer on roads and pavements, poses a significant danger to drivers and pedestrians during winter due to its transparency. We propose an efficient black ice detection system and technique utilizing Global Positioning System (GPS)-reflected signals. This system consists of a GPS antenna and receiver configured to measure the power of GPS L1 band signal strength. The GPS receiver system was designed to measure the signal power of the Right-Handed Circular Polarization (RHCP) and Left-Handed Circular Polarization (LHCP) from direct and reflected signals using two GPS antennas. Field experiments for GPS LHCP and RHCP reflection measurements were conducted at two distinct sites. We present a Normalized Polarized Reflection Index (NPRI) as a methodological approach for determining the presence of black ice on road surfaces. The field experiments at both sites successfully detected black ice on asphalt roads, indicated by NPRI values greater than 0.1 for elevation angles between 45o and 55o. Our findings demonstrate the potential of the proposed GPS-based system as a cost-effective and scalable solution for large-scale black ice detection, significantly enhancing road safety in cold climates. The scientific significance of this study lies in its novel application of GPS reflection signals for environmental monitoring, offering a new approach that can be integrated into existing GPS infrastructure to detect widespread black ice in real-time.
        4,000원
        8.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study proposes a soil moisture retrieval method from ground reflection signals received by Global Positioning System (GPS) antenna modules consisting of an up-looking (UP) right-hand circular polarization (RHCP) and two down-looking (DW) RHCP and left-hand circular polarization (LHCP) signals. Field experiments at four different surface types (asphalt, grassland, dry soil, and moist soil) revealed that the DW RHCP and LHCP signals are affected by antenna height and multipath interference signals. The strength differences between the DW LHCP and UP RHCP signals were in good agreement with the DW LHCP signals. Methodologically, this study applied a spectrum analysis to the detrended surface-reflected signals for RHCP and LHCP. The study indicated that the down-looking antenna exhibited greater sensitivity to reflected GPS signals than the up-looking antenna. We demonstrated the feasibility of estimating soil moisture using GPS signals, by comparing LHCP signals received by the down-looking antenna with theoretical values. This study presents a novel method for estimating soil moisture in vegetated areas, leveraging the advantage of crosspolarization comparisons to achieve stronger signal strength than single-polarization reflection signals. With further research, including long-term observations and detailed analysis, the proposed method has the potential to enhance performance significantly.
        4,600원
        9.
        2024.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Numerous research institutes have been studying semiconductor devices using two-dimensional materials for several years. However, the findings of these studies have yet to demonstrate the performance of digital devices that could replace silicon devices in the semiconductor industry. Nonetheless, the high carrier mobility and saturation velocity of 2-D materials remain attractive for semiconductor device performance, particularly in analog devices where these features can be utilized. In this research, we fabricated a phase-shift controller, a typical component of analog circuits, using 2-D materials and verified its operational characteristics. Analog circuits do not require large area integration, so we employed graphene, which has relatively simple formation and processing, as the 2-D material. Devices using graphene as a channel exhibit a V-shaped I–V characteristic, allowing for the input voltage to be adjusted to produce various modes of output characteristics. This means that the same devices can generate a phase-shifted output and an output with double the frequency by simply adjusting the input voltage range. This research is particularly meaningful since it demonstrates not only the potential of 2-D materials but also their potential for direct application to the semiconductor industry. These findings will contribute to the development of system IC technology and various applications.
        4,000원
        13.
        2024.04 구독 인증기관·개인회원 무료
        노지 나방류 해충인 담배거세미나방 방제를 위한 유충기생성 천적 2종인 긴등기생파리와 예쁜가는배고치벌 의 방사조건을 확립하고자 콩 재배포장에서 방사거리 및 방사밀도별 기생율을 조사하였다. 긴등기생파리는 방사 후 24시간 이내 방사지점으로부터 10m까지 이동하여 나방류 유충을 기생하였으며, 예쁜가는배고치벌도 방사지점으로부터 15m에서도 기주유충에 산란하여 고치가 형성된 것이 확인되었다. 긴등기생파리는 면적당 방사밀도가 높아질수록 기생율이 증가했으며, ㎡당 0.15마리(천적:해충=1:5) 방사했을 때 평균기생율 63.1%로 나타났다. 예쁜가는배고치벌은 긴등기생파리와 같은 방사밀도에서 평균기생율 47.8%로 확인되었으나, 방사 밀도에 따른 기생율 차이는 없었다.
        14.
        2024.04 구독 인증기관·개인회원 무료
        M. pruinosa has been found on 98 families and 345 species of plants, indicating a wide host range. Since its first report in a persimmon orchard in Gimhae in 2009, it had spread to 126 municipalities over 12,429 ha. Because of powerful dispersal ability, it’s difficult to control with insecticides. Therefore, it is necessary to reduce the population density through the release of M. pruinosa’s natural enemy, N. typhlocybae. N. typhlocybae females prey on or externally parasitize the nymphs of M. pruinosa. This natural enemy was introduced from Italy in 2017 through an international cooperative project between National Institute of Agricultural Sciences and University of Padova for controlling the sporadic pest, Metcalfa pruinosa. This study reported the results of mass rearing N. typhlocybae indoors and releasing them outdoors from 2020 to 2023 in 21 regions nationwide, showing an average parasitism rate of 27.3% and an average production of 7.9 cocoons per host, suggesting the possibility of their establishment in Korea.
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